Question 624691
Let {{{L}}} be the length, and {{{w}}} be the width.
If the length is 1.6 times the width, then
{{{L=1.6w}}}
If the sum of the length and with (in feet) is 130, then
{{{L+w=130}}}.
Substituting in the equation above, the expression {{{1.6w}}} for {{{L}}}, we get
{{{1.6w+w=130}}} --> {{{2.6w=130}}} --> {{{w=130/2.6}}} --> {{{highlight(w=50)}}}
Ten, substituting the value found for {{{w}}} in {{{L=1.6w}}} we find
{{{L=1.6*50}}} --> {{{highlight(L=80)}}}
The two equations we set up at the start form a system of linear equations:
{{{system(L=1.6w,L+w=130)}}}
and what we did above is solve it "by substitution".